Abstract: A bitline sense amplifier including: an amplifier which is connected between a first sensing bitline and a second sensing bitline, and detects and amplifies a voltage difference between a first bitline and a second bitline in response to a first control signal and a second control signal; and an equalizer which is connected between a first supply line through which the first control signal is supplied and a second supply line through which the second control signal is supplied, and pre-charges the first bitline and the second bitline with a precharge voltage in response to an equalizing control signal, wherein the equalizer includes an equalizing enable transistor in which a source terminal is connected to the first supply line and performs equalizing in response to the equalizing control signal.

Abstract: A power control method in a mobile communication system, which includes changing an original step size for adjusting a target quality of service (QoS) of a downlink channel to a larger step size when a wind-up power control process is released, and adjusting the target QoS using the changed step size when the wind-up is released.

Abstract: Methods and system for frame synchronization for a mobile communication system is disclosed. A downlink synchronization signal is detected. Multiple sub-frames on the basis of the detected synchronization signal are stored. An optimum position of a midamble sequence is detected using a correlation in accordance with sub-frames. A phase sequence of sub-frames is calculated by using a correlation value at the optimum position of the midamble sequence and a maximum correlation value of a synchronization signal. A frame synchronization is obtained on the basis of a phase position of a sub-frame. The frame synchronization is periodically updated.

Abstract: An AFC (Automatic Frequency Control) device of a QPSK modulation system including a frequency discriminating unit for calculating a real part peak value using frequency discrimination between adjacent I and Q signals of a received sequence and an imaginary part peak value using the frequency discrimination between adjacent I signals and adjacent Q signals, an error detecting unit for detecting an error symbol from the received sequence, and a switching unit for removing the detected error symbol under the control of the error detector. Also included is a frequency difference average calculating unit for calculating a frequency difference of the received sequence without the error symbol.

Abstract: The present invention discloses an apparatus for mapping and spreading data symbols in a mobile communication system which can improve efficiency of the system by performing data symbol mapping and spreading processes by using binary operations. The apparatus maps and spreads data symbols by using binary operations when quadrature phase shift keying modulation is performed in a mobile communication time division duplex mode.

Abstract: Methods and system for frame synchronization for a mobile communication system is disclosed. A cownlink synchronization signal is detected. Multiple sub-frames on the basis of the detected synchronization signal are stored. An optimum position of a midamble sequence is detected using a correlation in accordance with sub-frames. A phase sequence of sub-frames is calculated by using a correlation value at the optimum position of the midamble sequence and a maximum correlation value of a synchronization signal. A frame synchronization is obtained on the basis of a phase position of a sub-frame. The frame synchronization is periodically updated.

Abstract: An AFC (Automatic Frequency Control) device of a QPSK modulation system including a frequency discriminating unit for calculating a real part peak value using frequency discrimination between adjacent I and Q signals of a received sequence and an imaginary part peak value using the frequency discrimination between adjacent I signals and adjacent Q signals, an error detecting unit for detecting an error symbol from the received sequence, and a switching unit for removing the detected error symbol under the control of the error detector. Also included is a frequency difference average calculating unit for calculating a frequency difference of the received sequence without the error symbol.

Abstract: A channel estimation method and apparatus are provided in a Time Division Synchronous Code Division Multiple Access (TD-SCDMA) system. When signals are received from channel paths of each user, channel impulse responses of each user are estimated by using a single cyclic correlation on as many as a number of channel taps corresponding to a guard period. An estimate value of a tap corresponding to a midamble offset may be masked. Thus, even a channel path that has been further delayed than the midamble offset may be estimated and a channel estimation performance may be enhanced.

Abstract: A QPSK demodulation method and apparatus for a soft output in a 3G TDD HCR/LCR system calculates a position of a receiving symbol on a constellation and phase shifts the calculated symbol position. The phase shifted symbol position is then calculated, and the result is amplitude compensated. A soft output of an I component is calculated by subtracting an I component value and Q component value of the calculated symbol position, and a soft output of a Q component is calculated by adding I component value and Q component value. Thus, soft outputs of receiving bit data can be obtained from a simple calculation in QPSK demodulation of the TDD system.

Abstract: In a method for retrieving sequences having a minimum PAPR (peak to average power ratio) in an OFDM (orthogonal frequency division multiplexing) system, by using characteristics in which all sequences of the OFDM system are classified into cosets having the same PAPR, PAPRs of sequences in which early two elements are fixed as “0” are calculated. A sequence having a minimum PAPR is selected from among the calculated PAPRs, and sequences allocated to the coset in which the selected sequence is included are retrieved as sequences having the minimum PAPR. In addition, according to PAPRs of sequences having early two elements fixed as “0” and the number of sequences of a coset including the sequences having early two elements fixed as “0,” it is possible to quickly and efficiently analyze PAPR distribution of all sequences. Accordingly, the OFDM system can be designed as a device having a low PAPR and low dynamic range.

Abstract: The present invention discloses an apparatus for mapping and spreading data symbols in a mobile communication system which can improve efficiency of the system by performing data symbol mapping and spreading processes by using binary operations. The apparatus maps and spreads data symbols by using binary operations when quadrature phase shift keying modulation is performed in a mobile communication time division duplex mode.

Abstract: A system and method de-channelizes data in a W-CDMA system which uses an OVSF code. The method includes detecting an OVSF code used as a channelization code, demodulating data multiplexed in the OVSF code using an FHT, and mapping the order of the demodulated data so that it corresponds to the OVSF code. By restoring multiplexed data using FHT (Fast Hadamard Transform), complexity of calculations can be reduced and data can be quickly restored.